Pigs may infect humans with Swine flu

Discovery of new swine flu in Alta. pigs raises spectre that worriesexperts

9 hours ago

The discovery of the new swine flu in pigs on an Alberta farm raises aspectre that worries influenza experts: the possibility of the virusmoving back and forth between humans and pigs, giving it more chancesto mutate along the way.

About 220 pigs in a herd of 2,200 began showing signs of the flu April24, Canadian officials revealed over the weekend. A farmhand whotravelled to Mexico and fell ill upon his return is believed to haveinfected the pigs with the H1N1 influenza virus.

While the development did not come as a surprise to the World HealthOrganization or other experts, they expressed concern.

"We expected that at some point since this virus has swine viruselements that we would find possibly the virus in swine pigs in theregion where the virus is circulating," Dr. Peter Ben Embarek, a WHOfood safety scientist, said Sunday from Geneva.

Measures should be taken to prevent further human exposure to sickanimals because of a risk people around the pigs could becomeinfected, Embarek said.

"It has happened in the past with classical swine influenza," he said.

Dr. Ruben Donis, head of the molecular genetics branch of theinfluenza division at the US Centers for Disease Control, said themovement of a virus from one species to another creates moreopportunities for mutations.

While it isn't a given that any changes in the virus would mean itbecomes more virulent - causes more severe disease - that cannot beruled out, he said.

"It's possible," Donis said in an interview from Atlanta. "We have toconsider all options."

Donis was especially concerned about the virus getting seeded in pigpopulations on small farms that don't have the same level ofbiosecurity as larger operations.

Another worker on the Alberta farm subsequently fell ill, but it's notyet known if that person caught the swine flu.

The herd in central Alberta has been quarantined, and all of the pigsare recovering or have recovered. The farm worker has also recovered.

Meanwhile, Mexico's health secretary declared the swine flu outbreakto be declining in his country, though health officials warned againstcomplacency in combatting the spread of the disease.

There are no recommendations at this point from various agencies tocull pigs in Alberta or anywhere in the world, Embarek said.

He reassured the public that the virus is not a food-borne disease,saying there is no reason to be afraid of consuming pork products.

In Egypt police and armoured cars charged into a crowd of a 1,000irate pig farmers armed with stones and bottles Sunday.

Twelve people were injured as residents of a Cairo slum resistedgovernment efforts to slaughter the nation's pigs to guard againstswine flu.

Dr. Christopher Olsen, a swine flu expert at the University ofWisconsin-Madison, said having this H1N1 influenza A virus go backinto swine creates opportunities for it to pick up genetic mutationsor swap genes with other flu viruses. The latter process is calledreassortment.

"Putting it back into pigs creates more potential for geneticreassortment than in people alone," he said from Madison, Wis.

But even as the tally of people infected with swine flu continued torise Sunday - at least six other countries reported new cases -Mexico's health secretary said the swine flu epidemic in his country"is now in its declining phase."

Jose Angel Cordova said data suggest the epidemic peaked sometimebetween April 23 and April 28, and that drastic measures - closing thenation's schools, shuttering most of its businesses and banning masspublic gatherings - apparently have helped curb the flu's spread.

But Gregory Hartl, the WHO spokesman for epidemic and pandemicdiseases, cautioned against any premature declarations.

"That might be certainly what the current epidemiology is showing," hesaid from Geneva in response to Cordova's comments.

"I also would like to remind people that in 1918 the Spanish flushowed a surge in the spring and then disappeared in the summermonths, only to return in the autumn of 1918 with a vengeance."

It is estimated that upwards of 50 million people died in thatpandemic.

Hartl said there is a "high possibility" this H1N1 influenza A viruswill come back in colder periods.

"Maybe this current round of activity has peaked, but really, we areonly 10 days into the outbreak so we must wait and see," he said.

The death toll in Mexico remains at 19, and the number of confirmedcases has increased slightly, from 473 to 506.

Cordova said 12 of the dead were between 21 and 40 - unusual ages forpeople to die of the flu because they tend to have stronger immunesystems.

Three of the dead were children: a nine-year-old girl, a 12-year-oldgirl and a 13-year-old boy, said Pablo Kuri, a Mexican epidemiologistand adviser to Cordova. Four were older than 60.

Although most of the dead were from the Mexico City area, they camefrom different neighbourhoods in the metropolis of 20 million, andthere were no similarities linking their medical backgrounds.

One theory for the deaths is that perhaps they sought treatment toolate - falling sick an average of seven days before seeing a doctor.Many of the sick around the world were people who had recently visitedMexico.

In China more than 70 Mexican travellers were quarantined in hospitalsand hotels as part of that country's sweeping anti-swine flu measures.

Mexicans were being asked to identify themselves on arriving flightsand isolated from other travellers after landing, Jorge Guajardo, thecountry's ambassador to Beijing said Sunday.

Not even the country's diplomats have been immune. The Mexican consulgeneral in the southern city of Guangzhou was briefly held for checksafter returning from a Cambodian vacation last week, Guajardo said.